1 files changed, 36 insertions, 0 deletions

diff --git a/overlays/preserve-dscp/default.nix b/overlays/preserve-dscp/default.nix
new file mode 100644
index 00000000..7f956a12
--- /dev/null
+++ b/overlays/preserve-dscp/default.nix
@@ -0,0 +1,36 @@
+{ final, prev, sources, ... }:
+{
+  preserve-dscp = prev.stdenv.mkDerivation rec {
+    pname = "preserve-dscp";
+    inherit (sources.bpf-examples) version src;
+
+    patches = [ ./kern_env.patch ./kern_sec_classifier.patch ];
+
+    makeFlags = [ "PREFIX=$(out)" ];
+    buildFlags = [ "preserve-dscp" ];
+
+    CPATH = prev.lib.makeSearchPathOutput "dev" "include" (buildInputs ++ nativeBuildInputs);
+    BPF_CFLAGS = "-Wno-unused-command-line-argument -fno-stack-protector";
+
+    outputs = [ "out" "lib" ];
+
+    buildInputs = with final; [ elfutils libpcap zlib ];
+    nativeBuildInputs = with final; [ llvmPackages.clang llvmPackages.llvm pkgconfig bpftool libmnl gnum4 glibc_multi makeWrapper ];
+
+    installPhase = ''
+      mkdir -p $lib/lib/bpf
+      install -t $lib/lib/bpf \
+        preserve-dscp/preserve_dscp_kern.o
+
+      mkdir -p $out/bin
+      install -m 555 -t $out/bin \
+        preserve-dscp/preserve-dscp
+      wrapProgram $out/bin/preserve-dscp \
+        --set-default PRESERVE_DSCP_KERN $lib/lib/bpf/preserve_dscp_kern.o
+    '';
+
+    dontFixup = true;
+
+    meta.mainProgram = "preserve-dscp";
+  };
+}